From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57365) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XdXny-0004D5-SF for qemu-devel@nongnu.org; Mon, 13 Oct 2014 01:04:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XdXnp-0000zp-O0 for qemu-devel@nongnu.org; Mon, 13 Oct 2014 01:04:22 -0400 Received: from mail-pa0-x235.google.com ([2607:f8b0:400e:c03::235]:34191) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XdXnp-0000zf-Gw for qemu-devel@nongnu.org; Mon, 13 Oct 2014 01:04:13 -0400 Received: by mail-pa0-f53.google.com with SMTP id kq14so5214094pab.40 for ; Sun, 12 Oct 2014 22:04:12 -0700 (PDT) From: Jun Li Date: Mon, 13 Oct 2014 13:04:02 +0800 Message-Id: <1413176644-11031-1-git-send-email-junmuzi@gmail.com> Subject: [Qemu-devel] [PATCH v3 0/2] qcow2: Patch for shrinking qcow2 disk image List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, juli@redhat.com, famz@redhat.com, Jun Li , stefanha@redhat.com This is the third version for qcow2 shrinking. In this version, fixed host cluster leak when shrinking a disk image. Such as: Step 1, # /opt/qemu-git-arm/bin/qemu-img info /home/lijun/Work/tmp/shrink.qcow2 image: /home/lijun/Work/tmp/shrink.qcow2 file format: qcow2 virtual size: 2.0G (2147483648 bytes) disk size: 2.0G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false corrupt: false Step 2, # /opt/qemu-git-arm/bin/qemu-img resize /home/lijun/Work/tmp/shrink.qcow2 -100M Image resized. Step 3, # /opt/qemu-git-arm/bin/qemu-img info /home/lijun/Work/tmp/shrink.qcow2 image: /home/lijun/Work/tmp/shrink.qcow2 file format: qcow2 virtual size: 1.9G (2042626048 bytes) disk size: 1.9G cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false corrupt: false Step 4, # /opt/qemu-git-arm/bin/qemu-img check /home/lijun/Work/tmp/shrink.qcow2 No errors were found on the image. 31005/31168 = 99.48% allocated, 0.79% fragmented, 0.00% compressed clusters Image end offset: 2033844224 As above show, in step 1, "disk size" and "virtual size" are all 2.0G. After Step 3, "disk size" and "virtual size" are all 1.9G. BTW, above is also a simple testing. I will submit a test case for qemu-iotests later. But I am not so familar with howto write qemu-iotests now. In file block/qcow2.c, just using ftruncate to fix host cluster leak. In file block/qcow2-cluster.c, just re-copy qcow2_grow_l1_table to realize qcow2_shrink_l1_and_l2_table. In file block/qcow2-refcount.c, also update the realization to handle self-describing refcount blocks in function update_refcount. Thanks. Jun Li (2): qcow2: Add qcow2_shrink_l1_and_l2_table for qcow2 shrinking qcow2: add update refcount table realization for update_refcount block/qcow2-cluster.c | 173 +++++++++++++++++++++++++++++++++++++++++++++++++ block/qcow2-refcount.c | 44 +++++++++++++ block/qcow2.c | 40 ++++++++++-- block/qcow2.h | 2 + 4 files changed, 255 insertions(+), 4 deletions(-) -- 1.9.3